The invention relates to soft tissue repair and reconstruction. More particularly the invention relates to the fixation of a graft within a bone tunnel.
The repair and reconstruction of torn or damaged soft tissues is a common surgical procedure. For example, replacement graft ligaments may be secured at the site of the original ligament. The procedure generally involves drilling bone tunnels into adjacent bones at the site of the original ligament and securing within these bone tunnels a graft ligament. In many applications, such as in the knee joint, such procedures may be performed arthroscopically. The graft ligament may be an autograft, an allograft, a xenograft, and/or it may be totally artificial and synthetic. The most common types of graft ligaments include, for example, bone-tendon-bone grafts and soft tissue grafts such as semitendinosus and gracilis tendons. Both types are harvested by techniques well known to those skilled in the art. For example, repair of the anterior cruciate ligament (ACL) of the knee is often performed arthroscopically in a procedure which involves drilling a bone tunnel through the proximal tibia and into the distal femur. A variety of different types of graft ligaments may be secured in the bone tunnels in the femur and the tibia to replace the ACL.
Various fixation methods are used to secure the graft ligament within the femur and within the tibia. It is desirable that the fixation method be able to satisfactorily engage the bone in the wall of the bone tunnel or on the cortical bone surface. Consideration must be given to the fact that the bone may have only a thin layer of relatively hard cortical bone, such as in the anterior proximal surface and tibial plateau of the tibia. The bone may be otherwise relatively soft, cancellous bone. Depending upon the patient, the quality of the bone may vary considerably, particularly the cancellous bone. It would, therefore, be desirable to have a device capable of achieving fixation of the graft while eliminating the variability of fixation caused by the varying strength and density of cancellous bone.
Another consideration is that for biological graft fixation, that is, fixation resulting from tissue growing between the bone tunnel wall and the graft, some consideration should be given to facilitating such growth by enabling direct contact between the graft and the surrounding bone.